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International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6.14 | Impact Factor (2013): 4.438
Volume 4 Issue 5, May 2015
www.ijsr.net Licensed Under Creative Commons Attribution CC BY
Frequency Reconfigurable Antenna for
Multistandard Applications
Gagan D R1, Sujatha S
2
1M.Tech, Bangalore Institute of Technology, K R Road, V.V. Pura, Bengaluru,India
2Associate Professor, Bangalore Institute of Technology, K R Road,V.V. Pura, Bengaluru,India
Abstract: A reconfigurable yagi uda shaped microstrip antenna with switchable frequency is proposed. The proposed antenna has a
simple structure, consisting of a square radiating patch and parasitic conductors of rectangular shape. This antenna is designed for
multiband like WIMAX, GSM, GPS, FDMA and PCS. PIN diodes are used to switch frequencies between different bands depending on
the state of the PIN diode switch. The antenna structure proposed have return loss better than -10dB and VSWR below 3. TheAnsoft
HFSS 14software is used to model and simulate the proposed antenna.
Keywords: Microstrip patch antenna, Frequency Reconfigurable antenna, Return loss, VSWR, PIN diode.
1. Introduction
Antennas can necessary and critical components of
communication and radar systems. Arguably antennas are
categorized into nine different types. Each category of
antenna possesses its own inherent benefits and demerits that
make them more or less suitable for particular applications.
The antenna characteristics are fixed so there will be
restrictions on system performance. Making antenna
reconfigurable so that their behavior can adapt with changing
system requirements. Antenna can be reconfigured by
changing its frequency, polarization or radiation
characteristics by making use of some kind of switching
mechanism like pin diodes, RF MEMS, Varactor diodes etc.
Microstrip antennas are widely used to provide
reconfigurability due to their advantages of low profile, light
weight, low fabrication cost, and ease of integration with RF
devices. Frequency reconfigurability can be achieved by
adjusting the resonant frequency by changing the shape of
the radiating element. Switches are used to achieve
frequency selectivity by controlling the state of the switches,
switches can be pin diode, varactor diode or RF MEMS.
A simple frequency reconfigurable antenna which function at
UMTS/IMT 2000 and ISM Band using the principle of
controlling the antenna resonant frequency by PIN diodes
switches [4].The selection of different modes in [6] was
achieved by using either feed or ground switching. For
example, by using feed switching, the antenna can cover
global system for mobile communications (GSM) standard,
which are GSM850 and GSM900 for lower band and digital
cellular service (DCS) for upper band in mode 0.
Furthermore, GSM900 was covered for lower band while for
upper band, personal communication system (PCS) and
universal mobile telecommunications system (UMTS) was
covered in mode 1. Reconfigurable multiband slot dipole
antenna that can select a separate frequency bands is
proposed [7]. It can switch to single, dual or triple band
modes by using hard - wire switches. Switches are located in
the slot of the antenna which can control the arms of the
dipole either switch in and out from the slot edges. An open-
end straight slot line and the PIN diodes to achieve frequency
reconfigurable capability is proposed in [8]. The PIN diodes
along with DC bias network are located at specific positions
to create short circuit or open circuit across the slot. By
carefully controlling these diodes, the antenna operates as the
conventional λ/4 slot antenna. The design of a combined
frequency- and polarization reconfigurable antenna is
presented in [9]. Shorting posts around the patch are used to
enable the antenna to radiate three polarizations, and varactor
diodes are employed to achieve independent frequency
tuning for each polarization state.A compact Planar Inverted-
F Antenna (PIFA) suitable for cellular telephone applications
is presented in [10]. The quarter-wavelength antenna
combines the use of a slot, shorted parasitic patches and
capacitive loads to achieve multiband operation. The antenna
operates from 880 to 960 MHz and 1710 to 2170 MHz
covering GSM, DCS, PCS, and UMTS standards.A compact
five-band planar inverted-F antenna (PIFA) for mobile
phones using helical feeding and shorting lines, wide folded
patch, and two long slots is presented in [11]. The antenna
showed wide band characteristics covering DCN(824-894
MHz), GSM (880-960 MHz), DCS (1710-1880 MHz),
USPCS (1850-1990MHz), and WCDMA (1920-2170 MHz)
within 3.0:1 VSWR. And controlling the two slots showed
that the antenna’s low/high resonant frequencies can be
independently obtained.HFSS is a commercial finite element
method solver for electromagnetic structures. The software
includes a linearcircuit simulator with integrated optimetrics
for input andmatching network design. HFSS solver
incorporates apowerful, automated solution process, so we
need only tospecify geometry, material properties and the
desired output.From there, HFSS automatically generates an
appropriate, efficient and accurate mesh for solving the
problem using the selected solution technology [13].
In this paper presents a yagi Uda shaped microstrip
frequency reconfigurable antenna. This antenna employs
PIN diodes to switch its resonating frequency for different
standards like WIMAX, GSM, PCS, FDMA and GPS with
return loss below -10dB and VSWR below 3.The software
used to model and simulate the proposed antenna was Ansoft
HFSS 14.
Paper ID: SUB154086 350
International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6.14 | Impact Factor (2013): 4.438
Volume 4 Issue 5, May 2015
www.ijsr.net Licensed Under Creative Commons Attribution CC BY
2. Reconfigurable Antenna Design
The proposed reconfigurable antenna is designed using the
FR4 substrate with the dielectric constant of 4.4 and the
substrate thickness of 1.6mm on a ground dimension of
60x35mm^2 .
Antenna is fed by microstrip transmission line feed technique
with transmission line width of 3mm and length 21.5mm.
The optimal dimension of the proposed antenna is shown in
table 1.
Table 1:The optimal dimensions of the proposed
antenna Width (mm) Length (mm) Gap (mm)
w=26.08 h=20 -----
w1=24 h1=4 g1=2
w2=22 h2=2 g2=1
w3=20 h3=2 g3=1
w4=18 h4=2 g4=1
The proposed antenna has square radiating patch along with
four parasitic patches. Frequency reconfigurability is
achieved by varying the electrical length of patch antenna
depending on the state of the PIN diodes. The geometry of
the proposed antenna is shown in figure 1.
Figure 1: Geometry of the proposed reconfigurable antenna
By properly biasing the PIN diode, ON and OFF state of the
PIN diode is realised. For ON state, PIN diode is forward
biased which provide low impedance and acts as short. For
OFF state, PIN diode is reverse biased which provide high
impedance and acts as opencircuit. The equivalent circuit of
pin corresponds to an inductance L in series with a resistance
𝑅sfor the ON state and an inductance L in series with the
parallel connection of a capacitor 𝐶t and a resistance 𝑅pfor
the OFF state. According to the manufacturer, the diode
parameters are L=0.6 nH, 𝑅s =1.2Ω, 𝑅p= 15 kΩ and Ct=0.3
pF. The equivalent circuit of pin diode is shown in figure 2.
Figure 2: PIN diode equivalent circuits: (a) OFF state, (b)
ON state.
The software used to model and simulate the proposed
antenna was Ansoft HFSS 14, which is an industry-standard
simulation tool for 3D full-wave electromagnetic field
simulation.
3. Simulated Antenna Performance
The performance of the proposed antenna is characterized by
its electrical properties such as bandwidth, VSWR and return
loss.
Return loss is way of expressing the mismatch in
transmission line. It is the loss of signal power resulting from
the reflection caused at a discontinuity in a transmission line.
The return loss of the proposed antenna is below -10dB.
VSWR measures the relative size of the reflection. It is
closely related to the return loss. VSWR of the proposed
antenna is below 2dB. Bandwidth of an antenna is the range
of frequency over which the antenna can operate correctly.
When all the PIN diodes are OFF only square radiating patch
will radiate. It operates in the 3.5 GHz band with the return
loss of -19.5dB, VSWR of 1.84 and bandwidth of90MHz.
Fig.3.and Fig.4.shows simulated results for Return loss and
VSWR when all the diodes are OFF of the proposed antenna.
Figure 3: Return loss when all the diodes are OFF.
Figure 4: VSWR when all the diodes are OFF.
When PIN diode D1 is ON square radiating patch and
parasitic patch h1*w1 will be a single antenna and radiate. It
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
-20.00
-17.50
-15.00
-12.50
-10.00
-7.50
-5.00
-2.50
0.00
dB
(S(1
,1))
Ansoft LLC HFSSDesign1XY Plot 2
m 1
Curve Info
dB(S(1,1))Setup1 : Sw eep1
Name X Y
m 1 3.3200 -19.4535
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
dB
(VS
WR
(1))
Ansoft LLC HFSSDesign1XY Plot 1
m 1
Curve Info
dB(VSWR(1))Setup1 : Sw eep1
Name X Y
m 1 3.3200 1.8570
Paper ID: SUB154086 351
International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6.14 | Impact Factor (2013): 4.438
Volume 4 Issue 5, May 2015
www.ijsr.net Licensed Under Creative Commons Attribution CC BY
operates in the 1.8GHz band with the return loss of -
27.77dB, VSWR of 1.09 and bandwidth of 91MHz.
Fig.5.and Fig.6.shows simulated results for Return loss and
VSWR when diode D1 is ON of the proposed antenna.
Figure 5: Return loss when diode D1 is ON.
Figure 6: VSWR when diode D1 is ON.
Similarly Fig 7 to Fig 12 shows return loss and VSWR
simulated results when diode D1and D2 are ON which
operates in 1.6GHz band with return loss of -23.04 dB,
VSWR of 1.23 and bandwidth 77MHz, when diode D1, D2
and D3 are ON which operates in 1.4GHz band with return
loss of -23.84dB, VSWR of 1.35 of and bandwidth of
91MHz and when all the diodes are ON which operates in
1.3GHz band with return loss of -19.74, VSWR of 1.796 and
bandwidth of 73MHz.
Figure 7: Return loss when diodes D1 and D2 are ON.
Figure 8: VSWR when diodes D1 and D2 are ON.
Figure 9:Return loss when diodes D1, D2 and D3 are ON.
Figure 10:VSWR when diodes D1, D2 and D3 are ON.
Figure 11:Return loss when all the diodes are ON.
Figure 12: VSWR when all the diodes are ON.
Electric field distribution for each PIN diode condition is
Shown in Fig 13 to Fig 17. It can be concluded that as the
PIN diode ON electric field distribute over the parasitic
patch hence electrical length of the patch increases hence the
resonating frequency decreases.
Figure 13: Electric field distribution when all diodes are
OFF.
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
dB
(S(1
,1))
Ansoft LLC HFSSDesign1XY Plot 1
m 1
Curve Info
dB(S(1,1))Setup1 : Sw eep1
Name X Y
m 1 1.8300 -27.7051
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
dB
(VS
WR
(1))
Ansoft LLC HFSSDesign1XY Plot 2
m 1
Curve Info
dB(VSWR(1))Setup1 : Sw eep1
Name X Y
m 1 1.8410 1.0939
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
dB
(S(1
,1))
Ansoft LLC HFSSDesign1XY Plot 1
m 1
Curve Info
dB(S(1,1))Setup1 : Sw eep1
Name X Y
m 1 1.5800 -23.0445
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
dB
(VS
WR
(1))
Ansoft LLC HFSSDesign1XY Plot 2
m 1
Curve Info
dB(VSWR(1))Setup1 : Sw eep1
Name X Y
m 1 1.5800 1.2256
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
dB
(S(1
,1))
Ansoft LLC HFSSDesign1XY Plot 1
m 1
Curve Info
dB(S(1,1))Setup1 : Sw eep1
Name X Y
m 1 1.3700 -23.8405
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
dB
(VS
WR
(1))
Ansoft LLC HFSSDesign1XY Plot 2
m 1
Curve Info
dB(VSWR(1))Setup1 : Sw eep1
Name X Y
m 1 1.3800 1.3504
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
-20.00
-17.50
-15.00
-12.50
-10.00
-7.50
-5.00
-2.50
0.00
dB
(S(1
,1))
Ansoft LLC HFSSDesign1XY Plot 1
m 1
Curve Info
dB(S(1,1))Setup1 : Sw eep1
Name X Y
m 1 1.2600 -19.7416
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
dB
(VS
WR
(1))
Ansoft LLC HFSSDesign1XY Plot 2
m 1
Curve Info
dB(VSWR(1))Setup1 : Sw eep1
Name X Y
m 1 1.2600 1.7960
Paper ID: SUB154086 352
International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6.14 | Impact Factor (2013): 4.438
Volume 4 Issue 5, May 2015
www.ijsr.net Licensed Under Creative Commons Attribution CC BY
Figure 14: Electric field distribution when diode D1 is ON.
Figure 15: Electric field distribution when diodes D1 and
D2 are ON.
Figure 16: Electric field distribution when diodes D1, D2
and D3 are ON.
Figure 17: Electric field distribution when all diodes are
ON.
Simulations are performed using commercially available
package Ansoft HFSS 14,which is anindustry-standard
simulation tool for 3D full-wave electromagnetic field
simulation. The Pin-diode was modelled by the RFequivalent
circuit in order to take into account the non-ideal behavior of
the diodes.
The simulated results of the proposed antenna are shown in
table 2.
Table 2: The simulated results of the proposed antenna Switch
condition
Frequency
(GHz)
Return loss
(dB)
VSWR Bandwidth
(MHz)
All OFF 3.5 -19.45 1.84 90
D1 ON 1.8 -27.77 1.09 91
D1, D2 ON 1.6 -23.04 1.23 77
D1, D2, D3 ON 1.4 -23.84 1.35 91
All ON 1.3 -19.74 1.796 73
4. Conclusion
The proposed antenna achieves its goals of obtaining
frequency selectivity by electronically varying the effective
physical dimension of the microstrip antenna, thereby
resonating at different frequency. The resonant frequency is
tuned by changing the effective length of the antenna
radiator controlled by PIN-diodes switches. The proposed
antenna can work on different wireless standards like
WIMAX, FDMA, GPS, PCS and GSM. The proposed
antenna is a simple structure with good radiation
characteristics like VSWR, return loss and bandwidth.
5. Acknowledgement
Authors like to express their deep gratitude towards
theDepartment of Electronics and Communication
Engineering of Bangalore Institute of Technology for their
support and encouragement during this work.
References
[1] Jennifer T. Bernhard, Reconfigurable antennas, Morgan
and Claypool publishers, 2007.
[2] Constatine A. Balanis, Antenna theory Analysis and
Design, Third edition, Wiley India edition.
[3] David M. Pozar, Microwave Engineering, Second
edition, Wiley India edition.
[4] A. Mansoul and H. Kimouche, “A simple frequency
reconfigurable microstrip patch antenna for wireless
communication”, The 8th
International Workshop on
Systems, Signal Processing and their Applications 2013.
[5] Manaswini M Bhave, and R.G Yelalwar, “Multiband
reconfigurable antenna for cognitive- radio” Annual IEEE
India conference, 2014.
[6] A. C. K. Mak, C. R. Rowell, R. D. Murch, and C.-L.
Mak, “Reconfigurable multiband antenna designs for
wireless communication devices,” IEEE Transaction on
Antennas and Propagation, vol. 55, no. 7. pp. 1919–
1928, 2007.
[7] I. H. Idris, M. R. Hamid, M. H. Jamaluddin, M. K. A.
Rahim, and H. A. Majid “Multiband Reconfigurable
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[8] Keng-Hsien Chen, Sung-Jung Wu, Cheng-Hung Kang,
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[9] Pei-Yuan Qin, Y. Jay Guo, Yong Cai, Eryk Dutkiewicz,
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Paper ID: SUB154086 353
International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064
Index Copernicus Value (2013): 6.14 | Impact Factor (2013): 4.438
Volume 4 Issue 5, May 2015
www.ijsr.net Licensed Under Creative Commons Attribution CC BY
With Frequency and Polarization Agility” IEEE Antennas
and Wireless Propagation Letters, Vol. 10, 2011.
[10] P. Ciais, R. Staraj, G. Kossiavas, and C. Luxey,
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[11] Han, M.-S. and H.-T. Kim, "Compact five band
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Artech House of Antennas and Propagation, 1980.
[13] Ansoft High Frequency Structure Simulator(HFSS),
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Author Profile
Gagan D R received the B.E. degree in Electronics and
Communication Engineering from Reva Institute of Technology
and Management in 2013. Presently he is pursuing his final year M.
Tech in Digital Electronics and Communication from Bangalore
Institute of Technology and the proposed research work in this
paper is part of her M.Tech thesis. His area of interests includes
OFDM, MIMO systems and smart antenna design.
Sujatha S received the B.E. degree in Electronics and
Communication Engineering in 1988 and M.E. degree in
Electronics in 1992 from UVCE. She has working experience of 23
years as associate professor in Electronics and Communication
Engineering at Bangalore Institute of Technology. Her area of
interests includes communication, microwave and antennas.
Paper ID: SUB154086 354